/*!
 * jQuery throttle / debounce - v1.1 - 3/7/2010
 * http://benalman.com/projects/jquery-throttle-debounce-plugin/
 *
 * Copyright (c) 2010 "Cowboy" Ben Alman
 * Dual licensed under the MIT and GPL licenses.
 * http://benalman.com/about/license/
 */

// Script: jQuery throttle / debounce: Sometimes, less is more!
//
// *Version: 1.1, Last updated: 3/7/2010*
//
// Project Home - http://benalman.com/projects/jquery-throttle-debounce-plugin/
// GitHub       - http://github.com/cowboy/jquery-throttle-debounce/
// Source       - http://github.com/cowboy/jquery-throttle-debounce/raw/master/jquery.ba-throttle-debounce.js
// (Minified)   - http://github.com/cowboy/jquery-throttle-debounce/raw/master/jquery.ba-throttle-debounce.min.js (0.7kb)
//
// About: License
//
// Copyright (c) 2010 "Cowboy" Ben Alman,
// Dual licensed under the MIT and GPL licenses.
// http://benalman.com/about/license/
//
// About: Examples
//
// These working examples, complete with fully commented code, illustrate a few
// ways in which this plugin can be used.
//
// Throttle - http://benalman.com/code/projects/jquery-throttle-debounce/examples/throttle/
// Debounce - http://benalman.com/code/projects/jquery-throttle-debounce/examples/debounce/
//
// About: Support and Testing
//
// Information about what version or versions of jQuery this plugin has been
// tested with, what browsers it has been tested in, and where the unit tests
// reside (so you can test it yourself).
//
// jQuery Versions - none, 1.3.2, 1.4.2
// Browsers Tested - Internet Explorer 6-8, Firefox 2-3.6, Safari 3-4, Chrome 4-5, Opera 9.6-10.1.
// Unit Tests      - http://benalman.com/code/projects/jquery-throttle-debounce/unit/
//
// About: Release History
//
// 1.1 - (3/7/2010) Fixed a bug in <jQuery.throttle> where trailing callbacks
//       executed later than they should. Reworked a fair amount of internal
//       logic as well.
// 1.0 - (3/6/2010) Initial release as a stand-alone project. Migrated over
//       from jquery-misc repo v0.4 to jquery-throttle repo v1.0, added the
//       no_trailing throttle parameter and debounce functionality.
//
// Topic: Note for non-jQuery users
//
// jQuery isn't actually required for this plugin, because nothing internal
// uses any jQuery methods or properties. jQuery is just used as a namespace
// under which these methods can exist.
//
// Since jQuery isn't actually required for this plugin, if jQuery doesn't exist
// when this plugin is loaded, the method described below will be created in
// the `Cowboy` namespace. Usage will be exactly the same, but instead of
// $.method() or jQuery.method(), you'll need to use Cowboy.method().

(function(window,undefined){
	'$:nomunge'; // Used by YUI compressor.

	// Since jQuery really isn't required for this plugin, use `jQuery` as the
	// namespace only if it already exists, otherwise use the `Cowboy` namespace,
	// creating it if necessary.
	var $ = window.jQuery || window.Cowboy || ( window.Cowboy = {} ),

		// Internal method reference.
		jq_throttle;

	// Method: jQuery.throttle
	//
	// Throttle execution of a function. Especially useful for rate limiting
	// execution of handlers on events like resize and scroll. If you want to
	// rate-limit execution of a function to a single time, see the
	// <jQuery.debounce> method.
	//
	// In this visualization, | is a throttled-function call and X is the actual
	// callback execution:
	//
	// > Throttled with `no_trailing` specified as false or unspecified:
	// > ||||||||||||||||||||||||| (pause) |||||||||||||||||||||||||
	// > X    X    X    X    X    X        X    X    X    X    X    X
	// >
	// > Throttled with `no_trailing` specified as true:
	// > ||||||||||||||||||||||||| (pause) |||||||||||||||||||||||||
	// > X    X    X    X    X             X    X    X    X    X
	//
	// Usage:
	//
	// > var throttled = jQuery.throttle( delay, [ no_trailing, ] callback );
	// >
	// > jQuery('selector').bind( 'someevent', throttled );
	// > jQuery('selector').unbind( 'someevent', throttled );
	//
	// This also works in jQuery 1.4+:
	//
	// > jQuery('selector').bind( 'someevent', jQuery.throttle( delay, [ no_trailing, ] callback ) );
	// > jQuery('selector').unbind( 'someevent', callback );
	//
	// Arguments:
	//
	//  delay - (Number) A zero-or-greater delay in milliseconds. For event
	//    callbacks, values around 100 or 250 (or even higher) are most useful.
	//  no_trailing - (Boolean) Optional, defaults to false. If no_trailing is
	//    true, callback will only execute every `delay` milliseconds while the
	//    throttled-function is being called. If no_trailing is false or
	//    unspecified, callback will be executed one final time after the last
	//    throttled-function call. (After the throttled-function has not been
	//    called for `delay` milliseconds, the internal counter is reset)
	//  callback - (Function) A function to be executed after delay milliseconds.
	//    The `this` context and all arguments are passed through, as-is, to
	//    `callback` when the throttled-function is executed.
	//
	// Returns:
	//
	//  (Function) A new, throttled, function.

	$.throttle = jq_throttle = function( delay, no_trailing, callback, debounce_mode ) {
		// After wrapper has stopped being called, this timeout ensures that
		// `callback` is executed at the proper times in `throttle` and `end`
		// debounce modes.
		var timeout_id,

			// Keep track of the last time `callback` was executed.
			last_exec = 0;

		// `no_trailing` defaults to falsy.
		if ( typeof no_trailing !== 'boolean' ) {
			debounce_mode = callback;
			callback = no_trailing;
			no_trailing = undefined;
		}

		// The `wrapper` function encapsulates all of the throttling / debouncing
		// functionality and when executed will limit the rate at which `callback`
		// is executed.
		function wrapper() {
			var that = this,
				elapsed = +new Date() - last_exec,
				args = arguments;

			// Execute `callback` and update the `last_exec` timestamp.
			function exec() {
				last_exec = +new Date();
				callback.apply( that, args );
			}
			// If `debounce_mode` is true (at_begin) this is used to clear the flag
			// to allow future `callback` executions.
			function clear() {
				timeout_id = undefined;
			}
			if ( debounce_mode && !timeout_id ) {
				// Since `wrapper` is being called for the first time and
				// `debounce_mode` is true (at_begin), execute `callback`.
				exec();
			}

			// Clear any existing timeout.
			timeout_id && clearTimeout( timeout_id );

			if ( debounce_mode === undefined && elapsed > delay ) {
				// In throttle mode, if `delay` time has been exceeded, execute
				// `callback`.
				exec();

			} else if ( no_trailing !== true ) {
				// In trailing throttle mode, since `delay` time has not been
				// exceeded, schedule `callback` to execute `delay` ms after most
				// recent execution.
				//
				// If `debounce_mode` is true (at_begin), schedule `clear` to execute
				// after `delay` ms.
				//
				// If `debounce_mode` is false (at end), schedule `callback` to
				// execute after `delay` ms.
				timeout_id = setTimeout( debounce_mode ? clear : exec, debounce_mode === undefined ? delay - elapsed : delay );
			}
		}
		// Set the guid of `wrapper` function to the same of original callback, so
		// it can be removed in jQuery 1.4+ .unbind or .die by using the original
		// callback as a reference.
		if ( $.guid ) {
			wrapper.guid = callback.guid = callback.guid || $.guid++;
		}

		// Return the wrapper function.
		return wrapper;
	};

	// Method: jQuery.debounce
	//
	// Debounce execution of a function. Debouncing, unlike throttling,
	// guarantees that a function is only executed a single time, either at the
	// very beginning of a series of calls, or at the very end. If you want to
	// simply rate-limit execution of a function, see the <jQuery.throttle>
	// method.
	//
	// In this visualization, | is a debounced-function call and X is the actual
	// callback execution:
	//
	// > Debounced with `at_begin` specified as false or unspecified:
	// > ||||||||||||||||||||||||| (pause) |||||||||||||||||||||||||
	// >                          X                                 X
	// >
	// > Debounced with `at_begin` specified as true:
	// > ||||||||||||||||||||||||| (pause) |||||||||||||||||||||||||
	// > X                                 X
	//
	// Usage:
	//
	// > var debounced = jQuery.debounce( delay, [ at_begin, ] callback );
	// >
	// > jQuery('selector').bind( 'someevent', debounced );
	// > jQuery('selector').unbind( 'someevent', debounced );
	//
	// This also works in jQuery 1.4+:
	//
	// > jQuery('selector').bind( 'someevent', jQuery.debounce( delay, [ at_begin, ] callback ) );
	// > jQuery('selector').unbind( 'someevent', callback );
	//
	// Arguments:
	//
	//  delay - (Number) A zero-or-greater delay in milliseconds. For event
	//    callbacks, values around 100 or 250 (or even higher) are most useful.
	//  at_begin - (Boolean) Optional, defaults to false. If at_begin is false or
	//    unspecified, callback will only be executed `delay` milliseconds after
	//    the last debounced-function call. If at_begin is true, callback will be
	//    executed only at the first debounced-function call. (After the
	//    throttled-function has not been called for `delay` milliseconds, the
	//    internal counter is reset)
	//  callback - (Function) A function to be executed after delay milliseconds.
	//    The `this` context and all arguments are passed through, as-is, to
	//    `callback` when the debounced-function is executed.
	//
	// Returns:
	//
	//  (Function) A new, debounced, function.

	$.debounce = function( delay, at_begin, callback ) {
		return callback === undefined
			? jq_throttle( delay, at_begin, false )
			: jq_throttle( delay, callback, at_begin !== false );
	};

})(this);